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Subject[PATCH 1/2] mtd: nand: make Samsung SLC NAND usable again
Date
commit c51d0ac59f24 ("mtd: nand: Move Samsung specific init/detection
logic in nand_samsung.c") introduced a regression for Samsung SLC NAND
chips. Prior to this commit chip->bits_per_cell was initialized by calling
nand_get_bits_per_cell() before using nand_is_slc().
With the offending commit this call is skipped, leaving
chip->bits_per_cell cleared to zero when the manufacturer specific
'.detect' function calls nand_is_slc() which in turn interprets
bits_per_cell != 1 as indication for an MLC chip.
The effect is that e.g. a K9F1G08U0F NAND chip is falsely detected as
MLC NAND with 4KiB page size rather than SLC with 2KiB page size.

Add a call to nand_get_bits_per_cell() before calling the .detect hook
function in nand_manufacturer_detect(), so that the nand_is_slc()
calls in the manufacturer specific code will return correct results.

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
---
drivers/mtd/nand/nand_base.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 9900476..bcc8cef1 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -3820,10 +3820,13 @@ static void nand_manufacturer_detect(struct nand_chip *chip)
* nand_decode_ext_id() otherwise.
*/
if (chip->manufacturer.desc && chip->manufacturer.desc->ops &&
- chip->manufacturer.desc->ops->detect)
+ chip->manufacturer.desc->ops->detect) {
+ /* The 3rd id byte holds MLC / multichip data */
+ chip->bits_per_cell = nand_get_bits_per_cell(chip->id.data[2]);
chip->manufacturer.desc->ops->detect(chip);
- else
+ } else {
nand_decode_ext_id(chip);
+ }
}

/*
--
2.1.4
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